Abstract: Little is known about the effects of brief, repetitive laser pulses in the microsecond and sub-microsecond range on visual adaptation. Although it is generally acknowledged that, for pulsed light exposures from 1 to 150 ms, the... more
Abstract: Little is known about the effects of brief, repetitive laser pulses in the microsecond and sub-microsecond range on visual adaptation. Although it is generally acknowledged that, for pulsed light exposures from 1 to 150 ms, the total energy of a flash (intensity x ...
By reducing rod intrusion and improving efficiency of neural signaling throughout the visual system, macular pigment (MP) could improve many aspects of visual performance in low-light level conditions. We examined this possibility for... more
By reducing rod intrusion and improving efficiency of neural signaling throughout the visual system, macular pigment (MP) could improve many aspects of visual performance in low-light level conditions. We examined this possibility for spatial resolution, dark adaptation kinetics, and color detection. Twenty-seven subjects participated in the study. Spatial profiles of MP optical density (MPOD) were determined using heterochromatic flicker photometry. Mesopic- and scotopic-adaptation level experiments were conducted in Maxwellian view. Subjects with higher MP optical density (MPOD) required significantly lower contrast to detect the mesopic-level resolution targets; this effect became stronger with increasing spatial frequency. Dark adaptation recovery times were significantly faster as a function of MPOD (by nearly two minutes for the lowest mesopic-level task [high vs. low MPOD]; p < 0.001). Absolute scotopic thresholds were also significantly associated with MPOD (p < 0.001)...
Purpose: Disability glare spread functions have been developed using broadband white lights as sources. However, there is little information concerning the effect of wavelength with eccentricity, and multiple sources on disability glare.... more
Purpose: Disability glare spread functions have been developed using broadband white lights as sources. However, there is little information concerning the effect of wavelength with eccentricity, and multiple sources on disability glare. This study investigated disability glare effects for red and green laser sources with different visual angle separations and intensities. Additionally, disability glare effects were investigated with respect to right vs. left visual field placement of laser glare. Methods: A QUEST adaptive staircase algorithm was used in conjunction with a 2AFC task to determine contrast thresholds during glare exposure in nine healthy adult subjects. The stimulus was a stationary 4 cpd Gabor patch, subtending 1 degree of arc. Red (635nm) and green (532 nm) laser glare sources were placed 2.5, 5.0 and 10 degrees eccentric to the Gabor patch. Contrast thresholds were analyzed using univariate ANOVA [with an 8 (laser conditions) x 3 (eccentricities) x 2 (intensities) ...
Several hundred incidents involving the illumination of aircrew members by laser light have been reported in recent years. Consequently, Federal Aviation Administration (FAA) Order 7400.2 was revised to establish new guidelines for Flight... more
Several hundred incidents involving the illumination of aircrew members by laser light have been reported in recent years. Consequently, Federal Aviation Administration (FAA) Order 7400.2 was revised to establish new guidelines for Flight Safe Exposure Limits (FSEL) in specific zones of navigable airspace. The purpose of this study was to evaluate the performance of test subjects exposed to laser radiation while performing approach and departure maneuvers in the Critical Flight Zone (CFZ). Pilot performance was assessed in a Boeing 727-200, Level C, flight simulator using four levels of laser illumination (0, 0.5, 5, and 50 microW/sq cm) and three operational maneuvers (takeoff and departure, visual approach, and instrument landing system approach). Subjective responses were solicited after each trial and during an exit interview. The pilots were asked to rate on a scale from 1 to 5 (1=none, 2=slight, 3=moderate, 4=great, and 5=very great) the effect each laser exposure had on their...
: Contrast acuity and contrast sensitivity were measured in twelve subjects without and with eight different optical materials (OM) positioned in front of their right eye. The measurements were taken without and with light from a glare... more
: Contrast acuity and contrast sensitivity were measured in twelve subjects without and with eight different optical materials (OM) positioned in front of their right eye. The measurements were taken without and with light from a glare source present. The OM consisted of four haze standards with percent haze (H ) between approximately 1 and 20% and four reflective LEP with percent haze between 1 and 5%. In addition to H%, clarity, light scatter (log (s)) at scatter angles between 7-10 deg and the amount of scatter at angles from 1-70 deg (bi-directional transmission distribution function or BTDF) were measured. The scatter metrics, H%, log (s), and cumulative scatter beyond specific angles from the BTDF were plotted against changes in contrast acuity and contrast sensitivity between no OM (baseline) and OM viewing conditions with and without glare, which included measured change in visual performance between the Glare and No Glare conditions for each OM. The general effect of glare ...
